The Alaska lawsuit, filed in federal court in Anchorage, lists as plaintiffs four couples who were married outside Alaska and one unmarried couple. It alleges that Alaska's ban on same-sex marriage violates their rights to due process and equal protection under the U.S. Constitution.

The lawsuit seeks to bar enforcement of Alaska's constitutional ban on same-sex marriage. It also calls for barring enforcement of any state laws that refuse to recognize gay marriages legally performed in other states or countries or that prevent unmarried gay couples from marrying.

Alaska voters in 1998 approved a state constitutional amendment defining marriage as being between one man and one woman. But in the past year, the U.S. Supreme Court has struck down a provision of the federal Defense of Marriage Act that prevented legally married same-sex couples from receiving a range of federal benefits. Federal courts also have struck down state constitutional bans in a number of states, though appeals were pending in a number of cases. States such as Illinois and Hawaii legalized same-sex marriage.

An attorney for the couples, Caitlin Shortell, said lawsuits have been filed in almost every state with bans on same-sex marriage. A lawsuit in Alaska was seen by those involved as "necessary and important," Shortell said.

Another attorney, Heather Gardner, said in a statement that under current state law, "a couple who marries in Seattle and returns home to Alaska are married in the eyes of the law when their plane lifts off from SeaTac (airport) but are legal strangers when the flight touches down in Alaska. No Alaskan is a second-class citizen."

The plaintiffs are Matthew Hamby and Christopher Shelden; Christina LaBorde and Susan Tow; Sean Egan and David Robinson; Tracey Wiese and Katrina Cortez; and Courtney Lamb and Stephanie Pearson. Lamb and Pearson are unmarried.

Hamby, in a statement, said he and his husband — who, according to the lawsuit were married in Canada in 2008 and renewed their vows in Utah last year — are taking a stand "because marriage should be available to all loving couples. It's important to us that our family is recognized by the State of Alaska and that we have the same rights and privileges as others."

Defendants include Gov. Sean Parnell and Attorney General Michael Geraghty, who earlier this year told The Associated Press he would continue to defend the state's constitutional ban on same-sex marriage, even as federal courts around the country strike down similar bans.

The Alaska lawsuit was filed three days after a county circuit judge in Arkansas late Friday tossed out the 2004 constitutional amendment banning same-sex marriage, along with a 1997 state law. That state's attorney general filed paperwork Monday to at least temporarily preserve the ban.

Geraghty said he would not make his decisions based on federal district court decisions that still must be reviewed by appellate courts and perhaps the U.S. Supreme Court, which he expects will ultimately weigh in on the issue.

"Would everybody vote the same way today? Who knows? But it's on the books," Geraghty told the AP in February. He added: "Eventually, as I said, one day there will be guidance. I'm sure one day there will be a decision one way or the other. And when that happens, obviously we will comply with the decision."

A Parnell spokeswoman said by email late Friday afternoon that the governor's office had not been served with the lawsuit and the Department of Law would need time to review any it.

A proposal to strike the same-sex marriage ban from Alaska's constitution, introduced by Senate Minority Leader Hollis French, D-Anchorage, during the last legislative session, went nowhere. Republicans control both the Alaska House and Senate.